This invention relates generally to a system for inflating and for maintaining the inflation of pneumatic tires and more specifically to an automatic tire inflation system which requires no outside source of pressurized air.
Pneumatic tires have a maximum service life and provide the best vehicular handling and safety when properly inflated. While the procedure for checking tire pressure and adding additional pressurized air when required is relatively simple, it is frequently neglected to the detriment of the consumer. Furthermore, during intervals between pressure checks, tires will lose a certain amount of pressure. It would therefore be desirable to have an effective system for continuously and automatically monitoring and maintaining the air pressure in pneumatic tires.
Previous attempts have been made to provide automatic tire inflators. Prior art devices generally consist of pumping mechanisms disposed within the tire which are operated by the compression or flexing of the tire. A lever arm is often provided in such devices, extending across the tire either laterally or radially to operate a pump. The usual experience with these prior art pumping systems is that the constant impact from contact between the lever arm and the tire quickly damages both the tire and pumping mechanism. Many prior art devices are also overly complex or require highly specialized attachment or bellows arrangements to function. Examples of prior art tire inflators are found in U.S. Pat. Nos. 939,020; 1,029,340; 1,327,371; 1,456,567; 2,021,646; 2,420,224 and 4,269,252.
It would be advantageous to have an automatic tire inflator which is simple and rugged and operates without damaging impact between the inflator and the tire. It would also be advantageous to have such a tire inflator which will automatically stop operating when the correct tire pressure is reached. It would also be desirable to have a tire inflator which is light in weight and easily installed in a pneumatic tire.